Last week i went to my first trackday (at Zandvoort) and one of the things i noticed afterwards was that i couldn't tell my top speed or anything - i never looked or glanced at my speedo at all. Was quite a surprise, but the whole sensation just makes you forget about that needle (that and paying attention to the other cars on the track). It's all forces and sound that tell you when to throttle or brake.
Though I can imagine when you get used to driving fast for real, you start to have time to pay more attention to the little things like your exact speeds.
Though I can imagine when you get used to driving fast for real, you start to have time to pay more attention to the little things like your exact speeds.